This invention concerns improvements in fasteners for doors, windows and the like, and in particular fasteners of the type in which simultaneous longitudinal displacement of two bars in opposite directions is used to provide a fastening action to secure two members mounted for relative movement in a closed position.
In one fastener of the type specified, called an espagnolette, the bars comprise bolts mounted on one of the members and the fastening action is provided by moving the bolts to engage/disengage holes in or strikers attached to the other of the members to be secured.
In another fastener of the type specified, called a cremonne, the bars comprise apertured rails mounted on one of the members and the fastening action is provided by moving the rails to engage/disengage headed studs attached to the other of the members to be secured.
The known fasteners of the type specified, whether espagnolette, cremonne or any other kind, have a drive mechanism operable by a handle to displace the bars and various constructions of drive mechanism are known which will effect the required simultaneous displacement of the bars in opposite directions.
However the known drive mechanisms are often complex and in certain instances too large to be accomodated within the space available for mounting the fastener. This a particular problem where the fastener is to be mounted on a frame member consisting of a relatively thin and narrow extrusion.